ABSTRACT Suicide is the second leading cause of death for American Indian and Alaska Native (AI/ANs) ages 10-34, while rates for AI/ANs younger than 25 years are up to 6 times higher than for Whites of similar ages. Most research has been limited to rural reservation settings, yet 71% of AI/ANs reside in urban areas. This ?invisible tribe? faces unique challenges stemming from its lack of connection with traditional family and cultural environments. Urban AI/AN youth and young adults are at notably higher risk than their non-AI/AN counterparts for attempted suicide (21% vs. 7%), and for serious mental health problems, substance abuse, gang activity, teen pregnancy, and interpersonal abuse. Yet, most people who die by suicide have contact with a primary care provider in the prior year, and 45% are seen in the month before their death. ?Screening, Brief Intervention, and Referral to Treatment? (SBIRT) is an evidence-based practice that co-locates behavioral health clinicians in primary care teams and substantially reduces suicide risk through immediate intervention by behavioral health clinicians. However, retention in SBIRT has been a challenge and it has not been tested in urban AI/ANs to screen for suicidality (suicidal thoughts or behaviors). We have partnered with 2 large Urban Indian Health Organizations ? the Seattle Indian Health Board and First Nations Community Healthsource in Albuquerque to evaluate their existing SBIRT programs. We will also test a novel enhancement that sends caring text messages, which have been adapted from similar empirically-based, effective interventions for suicide prevention. The text messages are intended to improve SBIRT retention and increase social and cultural connectedness, which are strong protective factors against suicidality and death. During the 3-year study, we will randomly assign 2,400 AI/AN patients ages 12-34 who screen positive for suicidal ideation to usual care (SBIRT+referral to existing resources) or SBIRT with either 6 months (SBIRT+6) or 12 months (SBIRT+12) of text messages. Primary outcomes will be self-reported suicidal ideation, attempts, and suicide- related hospitalizations for 1 year after randomization. Secondary outcomes will include perceived social connectedness and retention. Given the value of sustainability, we will also conduct an economic evaluation. Our Specific Aims are to: 1) Evaluate SBIRT programs at our study sites to identify and address factors that affect their successful implementation; 2) Compare the effectiveness of SBIRT+6 and SBIRT+12 to usual care for reducing suicidal ideation, attempts, and hospitalizations; and for increasing social connectedness and retention in SBIRT; and 3) Perform an rigorous economic evaluation of SBIRT+6 and SBIRT+12 compared to usual care to examine their effects on use of healthcare resources and quality of life. Given the stigma attached to mental illness, few AI/AN youth and young adults seek help for suicidality. Challenges of retention and follow-up underscore the need for innovative means of engagement beyond the clinic. Our work is aligned with the Surgeon General's National Strategy for Suicide Prevention that identifies connectedness to others as the primary protective factor against suicidality.